An official statement from the US Navy's 7th Fleet said the tugboat lost its propulsion and drifted into the USS Benfold on Saturday, sustaining minor damage.

"No one was injured on either vessel and Benfold sustained minimal damage, including scrapes on its side, pending a full damage assessment," the statement read. The USS Benfold remains at sea while the Japanese boat was towed to a port in Yokosuka. The Navy said that the incident would be investigated.

This is the fifth such incident to take place this year, two of which have been fatal. The first took place on January 31 when the 31 USS Antietam ran aground, spilling 1,100 gallons of oil into Tokyo Bay, causing an estimated an estimated $4.2 million of damage. The second crash occurred on May 9, when the USS Lake Champlain collided with a South Korean fishing vessel in the Sea of Japan.